Abnormal haemoglobins produce a variety of anaemias which range in effect from being very mild to lethal. The most common of these are the sickle cell disorders and thalassaemias. In London, thalassaemia affects 3-5% of the Maltese population, 2-5% of the Italian population and 1-5% of the West Indian population respectively. Seventeen per cent of the Cypriot population carry a thalassaemia gene. Sickle cell disease occurs in 500:100 000 people in Britain's black population but is not exclusive to people of Afro-Caribbean origin. The gene is carried by 1 in 10 people. Sickle cell disease is statistically more prevalent among the host population than is phenylketonuria (10-12:100 000), hypothyroidism (20:100 000) and cystic fibrosis (62-63:100 000) in the general population. Although these diseases are routinely screened for at birth, there is no general strategy among district health authorities for sickle cell screening. It has been shown that of 76 health districts with a 3 +% ethnic minority population, 30 of which have an ethnic minority population of ‘over 10%’, only 6 have a comprehensive health care policy for people with sickle cell disease.